I know about re module in Python but it does not follow posix standard and PHP has removed ereg. Is there any library in any language which supports that? I think the closest is regex library in Java. Anyone knows about another? What would be the closest to use regular expressions such as those used in egrep in linux?
You should try regex library in python i think you can get posix-based regular expressions if you use POSIX flag. Here some documentation https://pypi.python.org/pypi/regex/